If you are seeing the Deleted media error message indicating that "You or a collaborate removed this media.", that simply means the file used in your edit can not be found in your account.
Potential reason #1
If you recently cleared some space in your Media tab and deleted a few media clips, you may have accidentally deleted a clip currently being used in an ongoing edit.
Potential reason #2
If you are in a Shared or Collaborative Project, it's possible that you are using shared media from the Project media folder that was deleted by another member of your project.
Potential reason #3
Your media was not yet fully imported into your account and there was an issue with the import process that resulted with a failure to save. This may have been triggered by a WiFi connectivity issue or a problem with your file.
How to fix this problem
If you try to finish an edit with deleted media, you will be prompted to replace the media before continuing forward.
To fix this problem, you will need to reimport the original media file you used. Once the file has successfully imported, you can then remove the deleted media from your Timeline and replace it with the newly imported file.
Alternatively, you can just use another media file as a replacement clip instead.
If you do not have access to the original media file, please feel free to contact our support team at firstname.lastname@example.org to see if there is anything we can do to help you restore your deleted media.